Gravesend remodelled

Gravesend station in Kent is a busy place. It is 28 miles from Charing Cross on the North Kent line through Dartford, London Bridge and Waterloo West. It is also used by the high-speed Javelin service, joining HS1 near Ebbsfleet to travel on to St Pancras. Writes Nigel Wordsworth

Ten trains an hour depart from Gravesend to one of the main London stations. A corresponding number call in going the other way, towards Faversham, Gillingham and Maidstone.

The station itself has only two platforms, one each side of the tracks, with two through roads in the centre.

Upgraded and lengthened

The North Kent line as a whole is being upgraded to take 12-car trains. This would involve platform extensions to both platforms. However, as the station is so busy and has a large London-commuter market, the decision was taken to add an extra platform.

The way this would be achieved would be to convert Platform 1 to a bay platform and renumbering it as Platform 0. The first through road would be removed and replaced by an island platform which, although it would be between the new bay and the remaining through road, would only access the latter which would be numbered Platform 1. Platform 2 would remain, but all three platforms would be built/extended for 12-car trains.

Multi-disciplinary construction specialists Spencer Rail was then awarded a design and build contract to take the project from Early Contractor Involvement stage through to completion.

Spencer brought Amey in for the track and signalling design work, undertaking the civils design in-house. Planning started in February 2013 under early contractor involvement, and work began on site in June with compounds being organised. As the contract progressed, the team would take over more and more of the station car park.

New footbridge

The initial work consisted of undertaking surveys, identifying any buried services that could cause problems, and clearing redundant ‘clutter’ from the site. An old water main, unused for 20 years, would come out and an old water tower structure needed to be demolished – however, the bricks would be saved.

Crossing the tracks between the two original platforms was an old, lattice footbridge. This was not DDA (Disability Discrimination Act) compliant and also, of course, didn’t access the new island platform. It would therefore have to go and be replaced by a modern bridge with lifts as well as stairs.

In fact, the footbridge would turn out to be one of the key elements of the project. All of the major work was planned for a 15-day blockade over Christmas and the New Year. However, Tom Kerins, Spencer’s operations director, explained that the prospect of bad weather during that time could prevent the project being completed.

“When we assessed risks to the project which could affect the whole job, the lifting operations, including lifting the new footbridge, came out as one of the highest risks. Bad winds over Christmas could jeopardise completion on time. So we brought that element forward – ahead of the main blockade.”

Lift shafts were constructed on both platforms to the west of the existing bridge while the station was in operation. Then, in week 34 (mid November) the new bridge was lifted in over a 27 hour possession.

Although the lifts were not operational, the steps were – so the new bridge could take the place of the old one. That was then dismantled over the next two weeks, an operation not without its challenges. “The station building was constructed around the footbridge,” Tom recalled. “So we had to make quite a complex plan to disassemble the old bridge and extract it from the station.”

There was good reason to be careful. As an historic item it was to be saved and sent to the East Kent heritage railway. That work was completed by the end of November, so that the station building and platforms could be made good, ready for the major work over Christmas.

Positioning the new footbridge early had the additional benefit of avoiding Christmas shopper syndrome. Gravesend has a very congested town centre, and having large cranes about the place during the last few shopping days could have caused additional disruption.

Blockade

With all the preparations in place, the blockade took effect at 01:30 on 22 December. A replacement bus service would operate between Ebbsfleet and Higham until 6 January.

Using a set of PEM-LEM machines, 200 metres of track was lifted from the through road which would be replaced by the new island platform. The track was not only saved but laid in the old Platform 1, which would become the new bay Platform 0, as that track was worn out and would be scrapped. All third-rail replacement was successfully carried out by Pod-Trak.

The second through road, which would be retained, was slewed over towards Platform 2 using road-rail vehicles. This created still more space for the island platform and, as the six-foot was quite wide in that location, it was not a difficult job to do.

Once clear, the site of the new platform was excavated down to the base chalk and strip foundations poured. That is, apart from around the site of the new footbridge. lift shaft where solid foundations were built to form a ‘coffin area’ – an anti-collision zone that would protect the bridge.

Once the foundations for the new platform were in place, and similar ones constructed for the extensions to the two existing platforms, the pre-cast concrete sections could be lifted into place. Delivered by Charcon before the blockade started, they were taking up most of the station car-park so it was good to start getting them moved.

A total of five cranes were on site, one 500 tonne and four 200 tonne supplied by Ainscough. The weather was so bad, with high winds and heavy rain, that four days of lifting were lost. However, by rescheduling other work, and positioning key platform elements using fork lift trucks, this didn’t delay the overall project.

The other heavy item was the third lift shaft for the footbridge. Once the platform elements were in place, this was hoisted into position with the lift car already inside it. Working with the lift supplier, and with an enormous amount of packing and packaging protecting it, everything went off without a hitch, it obviating the need to install the car separately while the station was going together around it.

Brickwork to the liftshafts was successfully completed in horrendous conditions by Civil Rail Solutions. A new motor room on the island platform would be completed later – using those saved heritage bricks.

Platforms and track

Miller Fabrications, which also manufactured the footbridge, supplied all the steelwork for the new platform canopies. This was also lifted in and then glazed in situ. Drainage was added, and the platforms fitted out with passenger information systems, CCTV, lighting and all the other mechanical and electrical services needed.

In the meantime, the trackwork was continuing. With all of it being moved or replaced (including the track on Platform 2), bringing in the eleven engineering trains had to be carefully planned so that there was a track to put them on.

Signalling was also reworked and repositioned by Amaro Signalling, working to Amey’s designs. The gantry across the platforms was removed, and several new sets of signals installed along with new S&C.

Because of the significance of the project, and the danger of it overrunning due to the weather, Network Rail’s route delivery director for Kent, Lenny Aristodemou, was a regular visitor to the site. On New Year’s Eve, the newly appointed chief executive of Network Rail, Mark Carne, came to have a look – his first ever visit on track at a railway work site.

Despite all of the challenges, Spencer Rail’s operations director had them covered. Working closely with Paul Devoy and David Lindsay of Network Rail, he took steps to make sure that the overall timetable was met. He added about 40 people to the 900 in total already employed on site and used road-rail vehicles in place of cranes where he could. As a result, the newly-rebuilt station was handed back in the early hours of 6 January, in time for the first train to enter the station at 04:33.

Despite the foul weather, and the additional hazard that brought, there were no reportable accidents during the blockade. Some tidying up remained – the lifts won’t be operational until February. However, Tom Kerins and his team from Spencer Rail can be justifiably proud of the work they did over a windy and soggy Christmas.